The purpose of this project is to further define the mechanics of peripheral blood phagocyte function that enable the polymorphonuclear (PMN) leukocyte to locomote and ingest particles. The emphasis will be on biochemical mechanisms involved in PMN leukocyte movement and ingestion by normal and abnormal PMN leukocytes. Based on the assumption that contractile proteins are the driving force behind ameboid movement, the plan is to isolate and characterize contractile proteins from mature PMN leukocytes and leukemic myeloblasts. Emphasis will be placed on further experiments based upon a preliminary observation that ice-cold sucrose extracts of cytoplasmic constituents of PMN leukocytes will gel when warmed to 25 degrees C. and that upon further incubation of 25 degrees C. the gelatinous extract will contract into a compact aggregate squeezing out fluid from the gel. Polyacrylamide gel electrophoresis with dodecyl sulfate revealed actin, myosin, and a peptide of M.W. 220,000 to comprise the major fractions of the contracted gel. To verify the role of the major peptides found in the gelatinous precipitate and aggregate of the extract supernatant, the contractile proteins will be purified and recombined in various permutations. Antibodies prepared against the various contractile proteins will be utilized to localize the distribution of the peptides at rest and during phagocytosis by employing the fluorescent and electron microscope. Contractile proteins in disease states suspected to be due to disordered PMN leukocyte and ingestive functions will also be studied.